The present invention relates to a screening procedure and apparatus for identifying children suffering from dysmetric dyslexia.
For well over a decade I have employed a technique disclosed in my U.S. Pat. No. 3,842,822 dated Oct. 22, 1974 by which dysmetric dyslexia was attributed to a cerebellar-vestibular dysfunction which I found can be detected by creating a subclinical nystagmus or eye vibration which resulted in the blurring of moving images when engaged in a reading type activity, i.e. visual fixation, tracking and sequential scanning, which induces the corresponding eye vibration or back and forth reading type eye movement. This movement or eye vibration occurs at a frequency or number of beats per second which can be controlled, being more specifically a function of the speed of movement of the material being visualized or read by the subject. Such induced eye vibration is maintained below the normal threshold level producing blurred vision in normal subjects, but which in additive relation to the subclinical eye vibration noted to exist in dysmetric dyslexic subjects, results in a total eye vibration at a frequency or number of beats per second above the threshold level. Accordingly, those subjects experiencing blurred vision during the reading process are automatically identified as possibly being dysmetric dyslexic.
After much experience I have discovered that contrary to the earlier thinking dysmetric dyslexic subjects have more than one blurring speed. While they have the same blurring speed as non-dyslexics do, i.e., a sequential blurring speed, in which a whole sequence of objects is seen as a panorama and the entire sequence blurs at once; they also have another blurring speed, which I call the single-targeting blurring speed . This latter phenomenon is a compensatory one, which takes over when the first, i.e., the reflexive, sequential tracking speed, is impaired. The single targeting blurring speed results from the observation that the subjects have an abnormally narrow lateral or peripheral span of vision. That is, they have practically no peripheral vision. This abnormality is observed when the subjects are forced to read a moving display and does not occur when reading a stationary display. For example, if the moving display is a continuous line of several discrete objects, the number of which in the field of vision always remaining the same, the subject would see less than the actual number displayed and when questioned as to the exact number seen, would provide an incorrect answer, since either the initial or the final members of the display (i.e. the peripheral members) would not be seen.
It is, therefore, the object of the present invention to provide a diagnostic procedure appropriate for individual or group examination for identifying dysmetric dyslexics employing the discovery mentioned above, namely, the inability of the subjects to maintain normal peripheral vision.
It is a further object of the present invention to provide a diagnostic procedure and apparatus for testing and identifying members of the subject groups having dysmetric dyslexia.
It is a further object of the present invention to provide a procedure and apparatus which is easily administered and which effectively screens individuals or members of large groups, particularly of children, for possible dysmetric dyslexia and to make a more rapid diagnosis of this affliction.
The foregoing objects and further objects as well as features and advantages of the present invention will be apparent from the following disclosure.